Honestly? We need not a successor of FHS but of filesystems, who are intimately tied package managers and installers. Zfs timidly start the change, with IPS (Image Package System) and BE (Boot Environments, as zfs clones), and we need to go much beyond that instead of wasting resources keeping up an '80s model like some do from btrfs to stratis. We need: - query-able storage, because search&narrow is the current way…
Who is "we?" I certainly don't need those things. If you need to add a bunch of complexity for your use case then feel free, but for most of us it's unnecessary.